【单选题】【消耗次数：1】
读写距离是RFID设备选型时较为关键的一个因素，通常读写距离在10mm至50cm之间的RFID系统采用：
①
低频
②
高频
③
超高频
④
微波
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RFID系统根据使用频率的不同，可分成低频RFID、高频RFID、超高频及微波RFID四种，日常使用的学校食堂饭卡系统通常属于()。
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